Greenland Sea moored tomography experiment

Abstract

As part of the Greenland Sea Project, a six‐element acoustic tomography array was deployed in the Greenland Sea during the period September 1988–September 1989. The purpose of the array was (1) to understand the circulation of the gyre, (2) to study the formation of the Greenland Sea Deep Water, and (3) to examine the features of acoustic propagation in an MIZ region over a yearly cycle. Supplementing the acoustic data, a number of other measurements were made. A year‐long time series of wind stress over the region was produced by the British Meteorological Office. Satellite SSM/I and AVHRR measurements produced information on ice parameters. A main component of the Greenland Sea Project was a seasonal series of CTD surveys, which the tomography effectively interpolates. The data analysis has already shown a number of interesting preliminary results. Examination of the wind stress data allows us to predict, on the basis of circulation models, what vorticity our array should measure—the agreement will be a test of the models. Work has begun on assimilating the tomographic data into ocean numerical models in order to constrain them. Two rather interesting events are seen in the acoustic data during the spring, which could be candidates for overturning, particularly given evidence from other data. (CTD profiles taken by Johannessen, Swift, and Meincke have shown evidence that deep convection to 1600 m did occur during the February to March time period in the center region of our array.) Acoustically, the interaction of the sound with the surface and surface mixed layer is of great interest. [Work supported by ONR and NSF.]